Everything you could possibly want to know about baking things including yeast. This was clearly a labour of love for Elizabeth David: it's a collection of recipes and anecdotes about baking from the last five hundred years or so, and includes at least one recipe for every traditional British bread and yeasted cake. I'm not sure why it's got "English" in the title, since Scottish and Welsh recipes are also adequately represented.
Each section has a detailed introduction, followed by the recipes, each annotated with adjustments for modern cookery and comments on how well it works (or, in some cases, why it couldn't possibly work as written but is still interesting). The introductory section on the basics of breadmaking -- how flour is produced, the differences between different types of flour, the various ways of leavening bread -- is worth the price of the book alone.
The only flaw is that the book dates from 1977, and is very much a product of the time: there's a lot of ranting about the poor state of British bread and flour production thirty years ago, and many substitutions are suggested that are no longer necessary. This doesn't detract from the value of the introductory information or the recipes, however, and I'd still strongly recommend this book if you're interested in cookery.
Mine's an original hardcover copy; the ISBN below is a more recent paperback reprint (of the same text).